ReCAPTCHA facts for kids

A ReCAPTCHA is a special test on websites. It helps tell the difference between a real person and a computer program (like a robot or bot). It was first created in 2007. When you see a ReCAPTCHA, it usually asks you to solve a small puzzle, often by looking at an image and typing what you see, or by clicking on certain pictures.

What is ReCAPTCHA?

ReCAPTCHA is a type of CAPTCHA. CAPTCHA stands for "Completely Automated Public Turing test to tell Computers and Humans Apart." Think of it as a quick quiz that only a human can easily pass. Websites use ReCAPTCHA to protect themselves from spam, fake accounts, and other bad things that computer programs might try to do.

Why Do Websites Use ReCAPTCHA?

Websites use ReCAPTCHA for several important reasons:

• Stopping Spam: It prevents bots from filling comment sections or forms with unwanted messages.
• Protecting Accounts: It helps stop automated programs from trying to guess passwords or create many fake user accounts.
• Keeping Things Fair: For things like buying concert tickets, it makes sure real people get them, not bots that buy them all up.

How Does ReCAPTCHA Work?

Over the years, ReCAPTCHA has changed how it works.

Old ReCAPTCHA Challenges

In the past, ReCAPTCHA often showed you two words that were hard to read. One word was a "control word" that the system already knew. The other word was from an old book or newspaper that computers couldn't read well. By typing both words correctly, you proved you were human. At the same time, you helped digitize old texts!

Modern ReCAPTCHA Challenges

Today, ReCAPTCHA is often much simpler for users. Sometimes, you just have to click a box that says "I'm not a robot." The system then looks at how you move your mouse, how long you take, and other small details to decide if you're human. If it's not sure, it might give you a harder puzzle, like:

• Clicking on all the pictures that show a traffic light.
• Typing numbers or letters from a distorted image.
• Solving a simple math problem.

This way, ReCAPTCHA tries to be easy for humans but very hard for robots.

Images for kids

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  An example of how an early ReCAPTCHA challenge looked in 2007, showing the words "following" and "finding". The wavy lines and extra marks made it harder for computers to read.

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  An image identification ReCAPTCHA where you might click on specific objects.

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  The "NoCAPTCHA reCAPTCHA" where you just click a box to prove you are not a robot.

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  An example of a ReCAPTCHA challenge from 2010, showing the words "and chisels".

See also

• In Spanish: ReCAPTCHA para niños